Electric switch-box.



J'LF. BURNS.

ELECTRIC SWITCH BOX. AFPLISAT'ION FILED DEC-3|. I912.

Patented Feb. 6,1917.

JAMES F. BURNS, or PHILADELPHIA, rnnnsxnvanm.

ELECTRIC swIrcH-Box.

To all whom it may concern:

Be it known that I,- JAMES Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Electric Switch-Boxes, whereof the followihg is a specification, reference being had to the accompanying drawing.

This invention relates to what are known in the electrical art as knock out boxes, to wit, boxes for inclosing electrical apparatus of various kinds and having portions of their walls partly cut through so that they may be readily knocked out to afford openings through which electrical conductors may be extended. My improvement relates particularly to such construction and arrangement of the weakened portions of the wall as to afford openings of different sizes, at a given point, by the provision of concentrically arranged knock out members thereat.

As hereinafter described my invention includes a metal box wall having a partially formed aperture normally closed by two concentric circular blanks, being respective knock out portions' of said wall, the outer blank being annular and connected with the remainder of the wall by' bridge, and the inner blank being a circular disk connected with the outer blank by an uncut unitary bridge; said two knock out blanks being disposed in respectively different planes with respect to said wall, the outer one of said blanks being displaced inwardly with respect to said wall, approximately one-half the thickness of the latter, and the inner blank being displaced outwardly with respect to said outer blank, approximately one-half the thickness of the latter; whereby, said inner blank may be knocked out, in turbing said outer blank and leaving a small opening in said wall, and, said outer blank may be knocked out, in the opposite direction, together with said inner blank, leaving a larger opening in said-,wall.

My invention includes the various novel features of construction and arrangement hereinafter more definitely specified.

In said drawing; Figure I is a plan view of a box, with its lid raised, conveniently embodying my invention.

Fig. II is an elevation of the left hand end of said box shown in Fig. I, but on a larger scale.

Specification of Letters Patent.

F. BURNS, of I an uncut unitary one direction, without dislation with the tions 17 but are Patented Feb. 6, 1917.

Application filed December 31, 1912. Serial No. 789,425.

a fragmentary vertical sectlonal view of said box, ,taken'on the line III, III in Fig. II.

Fig. IV is a, fragmentary vertical sectional view of said box, taken on the line IV, IV in Fig. II.

F1g. V is a fragmentary vertical sectional ligrewIof said box, taken on the line V, V in 1g. Fig. VI is a fragmentary horizontal sectional view of said box, taken on the line VI, VI in Fig. II.

Fig. VII is a fragmentary horizontal sectional view of said box, taken on the line VII, VII in Fig. II.

Fig. VIII is a fragmentary elevation of the end of said box shown in section in 1g, y Fig. IX is a fragmentary horizontal sectionalview of saidbox, taken on the line IX, IX in Fig. VIII.

In said figures; 1 is'the box having the front wall 2, opposite end walls 3 and 4, rear wall 5 and lid 6, the latter being pivotally connected with said box by the \pintles 8 which are riveted through the lugs 10 on Fig. III is the box and the lugs 11 on said lid, the latter being provided with the knob 13 by which it may be opened and'closed, and having at the front thereof the indentation '14: adapted to engage the: indentation 15 in said box so as to normally hold said lid shut. It is to be understood that when said lid is manually opened or shut the wall 2 springs sufliciently to permitthe disengagement or engagement of said indentations 14 and 15.

Said box' wall 3 is provided with two knock out portions 17 which are circular disks partly cut through said wall 3 but connected therewith by uncut unitary bridges 18, the latter being in unitary relation with both said wall 3 out portions 17. The lugs 19 diametrically opposite said bridges 18 are in unitaryrerespective knock out porsevered from the wall 3, as shown in Fig. III, being frictionally en gaged with said accidental displacement of said knock out members 17 which, as shown in Fig. III, are displaced inwardly with respect to said wall 3 approximately one-half the thickness of the latter.

Said wall 3 is also provided with two concentric circular knock out portions 21 and and the respective knock 22; the outer one being annular andconnected with the remainder of said wall by uncut unitary bridges 24, and the inner knock out member 22 being a circular disk connected with said outer member 21 by the uncut unitary bridge 26.. The lug 27 diametrically opposite said bridge 26 is in unitary relation with the knock out blank 22 but is severed from the blank 21, as indicated in Fig. IV, being frictionally engaged therewith to prevent accidental displacement of said-blank 22. As shown in Fig IV said two knock out posed in respectively difl'erent planes with respect .to said wall 3; blank 21 being dis placed inwardlyz with respe'ctto sa1d wall, approximately one-halfthe thickness of the latter; and blank 22 being dlsplaced 1nwardly with respect to said blank 21 approximately one-half the thickness of the latter.

As shown in Figs. V, VIII and IX saidbox wall 4 isprovided with two knock out blanks 30 and 31 which are similar to the blanks 21 and22 above described except that the inner blank 31 is displaced with respect to the outer blank 30 with which it is connected by the uncut unitary bridge 32 shown in Figs. V and VIII; said outerblank 30 beingconnected' with said wall 4 by the uncut unitary bridges 34 shown in Fig. VIII; whereby, said inner blank may be knocked out, in one direction, to wit, outwardly; without disturbingsaid outer blank and leaving a small opening in said wall 4, and, said outer blank 30 may be lmocked out, in the opposite direction, to wit, inwardly with respect to the box, to-

gether with said inner blank'31, leaving a larger opening in sa d wall.

Said smaller blanks 17, 22 and 31 may :be

knocked out to receive, in spaced relation, the several wires of an open work installation; without disturbing the larger blanks 21. It

may be observed that smaller blanks 17, 22

and '31 being unitarily connected with the box walls only at one side and frictionally held at the diametrically opposite sides it is easier to knock out them than the largerblanks 21 and 30 as the bridges 18 and 26.

readily break off as said smaller blanks are knocked out. As all of the bridges .24 and 34 of said larger blanks are primarily uncut,

A I find it convenient to nick them, with a cold chisel, preliminary to knocking out said larger blanks to aflord larger openings to receive conduits in which may be inclosed all of the wires which in open work would be extended through the smaller openings in spaced relation. However, it is to be understood that it is possible to, knock out "thelarger blanks aforesaid without'nicking the bridges as aforesaid although greater care must be exercised, in that case, to avoid bending the box wall. It may be observed blanks 21 and 22 are disoutwardly that the circumferential extent of each of said elements 18, 19, 24, 26, 27 and 34 is limited by cuts in the versely to the perimeters of the respective blanks and inwardly with respect to said perimeters, v stresses upon said elements and minimize such stresses upon the box wall.

I do not desire to limit myself to the precise details of construction and arrangement herein set forth as it is obvious that various modifications ma be made therein without departing from t e essential features of my invention'as defined in-the appended claims.

I claim 1.-An electric connection box having a metal wall with a. partiallyflformed aperture nbrmally closed by two concentric cirblank beinga disk connected'with said outer blank by an uncut'unitary bridge intermediate of said outer bridges and having, diametrically opposite to it, a lug frictionally engaging sa1d wall; said two blanks being disposed in respectively dilferent planes withrespect to said wall, the outer one of said'blanks being displaced inwardlywith respectto said wall, and the inner blank being displaced outwardly with respect'to said outer blank; whereby, said inner blank may be knocked out, in one direction, without disturbing said outer blankand leaving a small opening in said wall, and, said outer blank may be knocked out, in the opposite direction, together with said inner blan'k, leaving a larger opening in said wall.

2. An electric connection boxhaving a metal wall with a partially. formed aper-,

ture normally closed by two concentric circular blanks, the outer blank being annular and connected with the remainder of the wall by three uncut unitary bridges, equallyspaced circ'umferentially, and the inner blank being a disk connected with said outer blank by an uncut unitary bridge intermediate of said outer'bridges and having,diametrically opposite to it, a lug frictionally engaging said wall said two blanks being disposed in respectively difierent planes w1th respect to said wall, the inner,

metal extending trans- EEO IQDU

blank being displaced outwardly with respect to said outer blank; whereby, said inner blank may be knocked out without disturbmg said outer blank and leaving a small opening in said wall, and said outer blank may be knocked out, together with said inner blank,.leaving a larger opening insaidwall. 3. 'An electric connection box having a metal wall with a partially formed aperture normally closed by two concentric circular blanks, the outer blank being annular and engaging said wall; said two blanks ally engaging said wall;

connected with the remainder of the Wall by three uncut unitary bridges, equally spaced circumferentially, and the inner blank being a disk connected with said outer blank by an uncut unitary bridge intermediate of said outer bridges and having, dia metrically opposite to it, a lug frictionally being disposed in respectively different planes with respect to said wall; whereby, said inner blank may be knocked out without disturbing said outer blank and leaving a small opening in said wall, and said outer blank may be knocked out, together with said inner blank, leaving a larger wall.

4. An electric connection box having a metal wall with apartially formed aperture normally closed by two blanks, one within the other, the outer blank being annular and connected with the remainder of the wall by three uncut unitary bridges, equally spaced cii'cumlferentially, and the inner blank being a disk connected with said outer blank by an uncut unitary bridge intermediate of said outer bridges and having, diametrically opposite to it, a lug frictionsaid two blanks being disposed in respectively different planes with respect to said wall, the outer one of said blanks being displaced inwardly with respect to said wall, and the inner blank being displaced outwardly with respect to said outer blank; whereby, said inner blank may be knocked out, in one direction, without disturbing said outer blank and leaving a small wall, and, said outer blank out, in the opposite direction, together With said inner blank, leaving a larger opening in said wall.

5. An electric connection box having a metal wall with a partially formed aperture normally closed by two blanks, one Within the other, the outer blank being annular and connected with the remainder of the wall by three uncut unitary bridges, equally spaced circumferentially, and the inner blank being a disk connected with said outer blank by an uncut unitary bridge intermediate of said outer bridges and having, diametrically opposite ally engaging said Wall; said two blanks being disposed in respectively different planes with respect to said Wall, the inner blank being displaced outwardly with respect to said outer blank; whereby, said inner blank may be knocked out without disturbing said outer blank and leaving a small opening in said wall, and said outer blank may be knocked out, together with said inner blank, leaving a larger opening in said wall.

' 6. An electric connection box having a metal wall with a partially formed aperture normally closed by opening in said may be knocked gaging said wall; posed in respectively different planes wlth respect to said wall; whereby, said inner opening in said bridge and having,

to it, a lug friction-' two blanks, one within the other, the outer blank being annular and connected with the remainder of the Wall by three uncut unitary bridges, equally spaced circumferentially, and the inner bla-nk being a disk connected with said outer blank by an uncut unitary bridge intermediate of said outer bridges and having, diametrically opposite to it, alug frictionally ensaid two blanks being disblank may be knocked out without disturbing said outer blank and leaving a small opening in said wall, and said outer blank may be knocked out, together with said inner blank, wall.

7. An electricconnection' box having a metal wall with a partially formed aperture closed by two blanks, one within the other, the outer blank being connected with the remainder of'the wall by an uncutunitary bridge, and the inner blank being connected with said outer blank by an uncut unitary diametrically opposite to its bridge, a lug offset from the plane of said inner blank and frictionally engaging said outer blank; said two blanks being disposed in respectively different planes with respect to said wall.

8. An electric connection box having a metal wall with a partially formed aperture closed by two blanks, one within the other, the outer blank being connected with the remainder of the wall by-an uncut unitary bridge, and the inner blank being connected with said outer blank by an uncut unitary bridge and having, diametrically opposite to its bridge, a lug offset from the plane of said inner blank and frictionall'y engaging said outer blank.

9. An electric connection box having a metal wall with a partially formed aperture normally closed by two blanks, one within the other, the inner blank beingconnected with said outer blank by anuncut unitary bridge and having, diametrically opposite to its bridge, a lugoffset from the plane of said inner blank and frictionally engaging said outer blank; said two blanks being disposed in respectively different planes with respect to said wall.

10. An electric connection box having atwo blanks, one within and frictionally engaging rename ginof said aperture and having, diametriversely to the perimeters of the respective cally opposite to it, a lug oifset from the blanks, and inwardly with respect to said plane of said blank and frictionally engagperimeters. v

ing said margin. 17 An electric connection box having a 12. An electric connection box having a metal wall with a partially formed aper- W metal wall with a partially formed aperture ture normally closed by two blanks, one

normally closed by a blank having an uncut within the other, the inner blank being unitary bridge connecting it with the marconnected with said outer blank by an ungin of said aperture and having a lug offset cut unitary bridge and having, diametrically from the plane of said blank and frictionally opposite to said bridge, a lug offset from the :engaging said margin. plane of said inner blank and frictionally 13. An electric connection box having a. engaging said outer blank, and the circummetal wall with a partially formed aperture ferential extent of said bridge and lug being normally closed by a blank having an uncut limited by cuts in the metal extending transunitary bridge connecting it with the marversely to the perimeters of the respective 30 gin of said aperture and having a lug .ofi'set blanks.

from the plane of said blank and frictionally 18. An electric connection box having a engaging said margin remote from said metal wall with a partially formed aperture bridge; said aperture being disposed c'onnormally closed by a blank having an uncut jcentrically within another partially formed unitary bridge connecting it with the maraperture normally closed by a blank having gin of said aperture and having, diametrian uncut unitary bridge connecting the latcally opposite to it, a lug offset from the ter blank with the margin of the latter aperplane of said inner blank and frictionally ture. engaging said margin; the circumferential 14. An electric connection box having a extent of said bridge and lug being limited metal wall with a partially formed aperby cuts in the metal extending transversely ture normally closed by two blanks, one to said margin and inwardly with respect within the other, the inner blank being conthereto. v i

nected with said outer blank by an uncut 19. An electric connection box having a unitary bridge and having, diametrically opmetal wall with a partially formed aper- 5 posite to said bridge, a lug offset from the ture normally closed by a blank having an plane of said inner blank and frictionally uncut unitary bridge connecting it with the engaging said outer blank; said two blanks margin of said aperture and having, diabeing disposed in respectively difierent metrically opposite to it, a lug oifset from planes with 'respet to said wall, and the the plane of said inner blank and frictiona circumferential extent of said bridge and ally engaging said margin; the circumferlug being limited by cuts in the metal exential extent of said bridge and lug being tending transversely to the perimeters of the limited by cuts n the metal extending transrespective blanks, and inwardly with re- Versely to said margin. v spect to said perimeters. 20. An electric connection box having a 05 15. An electric connection box having a metal wall with a partially formed apermetal wall with a partially formed aperture ture normally closed by a blank having an normally "closed by two blanks, one within uncut unitary bridge connecting it with the other, the inner blank being connected e margin of said aperture and having a with said outer blank by an uncut unitary lug ofiset from the plane of said blank and bridge and having, diametrically opposite frictionally engaging said margin; the cirto said bridge, a lug ofiset from the plane cumferential extent of said bridge and lug of said inner blank and frictionally engagbeing limited by cuts in the metal extending 1mg said outer blank; said two blanks being transversely to said margin and inwardly disposed in respectively difierent planeswith with respect thereto. respect to said wall, and'the; circumferential 21. An electric connection box having a extent of said bridge and lug being limited metal wall with a partially formed aperby cuts in the metal extending transversely ture normally closed by a blank having an to the perimeters of the respective blanks. uncut unitary bridge connecting it with the 16. An electric connection box having a margin of said aperture and having a lug 120 Jmetal wall with a partially formed aperoffset from the plane of said blank and fricture normally closed by two blanks, one tionally engaging said margm.

within the other, the inner blank being con- 22. A box having a metal wall with a par:

nected with said outer blank by an uncut tially formed aperture normally closed by unitary bridge and having, diametrically two blanks, one within the other, the inner 12:

opposite to said bridge, a lug ofiset from the blank being connected with said outer blank plane] of said inner blank and frictionally by an uncut unitary bridge and having, diaengaging said outer blank, and the circummetrically opposite to said bridge, a lug ofi ferential extent of said bridge and lug being set from the plane ofsaid inner blank and l limited by cuts in the metal extending transfrictionally engaging said outer blank; said 1311 outer blank being connected with said wall by a plurality of uncut unitary bridges, equally spaced circumferen-tially at the junction of said blank and wall; said .two blanks being respectively planular except at their bridges and being disposed in respectively difierent planes with respect to said wall, and the circumferential extent of each of said'bridges and said lug being limited by 0 cuts in the metal extending transversely to the perimeters of the respective blanks,' and lnwardly with respect to said perimeters.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this twenty-seventh day of her, 1912. I

' JAMES F. BURNS. Witnesses:

FRANKL. ALBERT, CLARENCE W. SHIox;

Decem- 15 

